Geochemistry of basalts from the Dumisseau Formation, southern Haiti: implications for the origin of the Caribbean Sea crust Article

Sen, G, Hickey-Vargas, R, Waggoner, DG et al. (1988). Geochemistry of basalts from the Dumisseau Formation, southern Haiti: implications for the origin of the Caribbean Sea crust . EARTH AND PLANETARY SCIENCE LETTERS, 87(4), 423-437. 10.1016/0012-821X(88)90006-4

cited authors

  • Sen, G; Hickey-Vargas, R; Waggoner, DG; Maurrasse, F

authors

abstract

  • Basalt and diabase from the Cretaceous Dumisseau Formation, southern Haiti have Mg-numbers of 43-63, TiO2 contents of 1.6-3.9% and La abundances of 3.6-15.3 ppm. La Ta ratios average 10, and indicate that the basalts are oceanic in character, distinct from the arc associations forming the northern part of Haiti. Oldest lavas have low TiO2 (1.6%) and are LREE-depleted, similar to N-MORBs, whereas overlying lavas have higher TiO2 (2-3.9%) and are LREE-enriched, similar to E-MORBs or hotspot basalts. 87Sr 86Sr ratios vary from 0.70280 to 0.70316, 143Nd 144Nd from 0.512929 to 0.513121, and 206Pb 204Pb from 19.00 to 19.27. LREE-depleted lavas have high 143Nd 144Nd (0.51309-0.51310) typical of MORBs, whereas 143Nd 144Nd in the LREE-enriched lavas varies widely (0.512929-0.513121). Chemical features of the Dumisseau basalts are equivalent to those of Caribbean seafloor basalts recovered on DSDP Leg 15, and support the contention that the Dumisseau is an uplifted section of Caribbean Sea crust. Oldest lavas are analogous to MORB-like basalts cored at Leg 15 Sites 146, 150, 152 and 153, and the overlying lavas are analogous to incompatible-element-enriched basalts cored at Site 151 on the Beata Ridge. Isotopic compositions of the Dumisseau basalts overlap with those of the eastern Pacific Galapagos and Easter Island hotspots. However, the presence of N-MORB basalts in the lower part of the Dumisseau and at the majority of Leg 15 Sites indicates that the anomalously thick Caribbean crust probably did not originate as a hotspot-related basaltic plateau, but may have been generated by on-ridge or near-ridge hotspot magmatism. © 1988.

publication date

  • January 1, 1988

published in

Digital Object Identifier (DOI)

start page

  • 423

end page

  • 437

volume

  • 87

issue

  • 4